Shale gas drilling picked up steam in Pennsylvania nearly a decade ago, but some communities are just now experiencing development. Many residents in Penn Township, a rural-residential suburb about 20 miles east of Pittsburgh, are trying to fight it. PublicSource has followed the events there since April 2015. We placed air quality sensors at five homes to monitor pollutants near the contested well pad for two months. In this series, we will explain the ongoing drilling debate in Penn Township and delve further into the possible effects of drilling on air quality.